This invention relates to blends of an aromatic polycarbonate with a rubber, a monovinylidene aromatic copolymer and a polar polymer.
The polycarbonates of dihydric phenol such as bisphenol-A, which are described in U.S. Pat. No. 3,028,365, are known to be useful in the manufacture of molded plastic parts. Such resins are notably tough and have moderately high softening temperatures. Unfortunately, however, as a result of their relatively poor melt flow characteristics, such polymers are generally more difficult to mold than is often desirable. Also, such aromatic polycarbonates are relatively expensive materials.
Previous attempts to improve melt flow characteristics of these aromatic polycarbonates have generally involved incorporating a lower melting, less expensive polymer into the polycarbonate. See, for example, U.S. Pat. Nos. 3,130,177; 3,239,582; 3,966,842 and 3,862,998. The blends resulting from such attempts generally exhibit improved melt flow properties at the sacrifice of other desirable features such as heat resistance, impact strength and the like.
In view of the deficiencies of conventional polycarbonates and blends thereof, it would be highly desirable to provide an economical polycarbonate composition which exhibits improved processability while retaining most of the physical properties characteristic of the original polycarbonate.